Among a plurality of methods of detecting an object, a time of flight (TOF) method of measuring the distance using the time of flight, which is the period taken for go and return of light from the object, is known.
Patent Literature 1 discloses a conventional technology for dividing a light reception signal time into three or four light reception signal periods of different phases that are shorter than the light emission signal time, and calculating a distance measurement value on the basis of the light quantities acquired in the light reception signal periods.